RO Storage Tank Both Float Switches Internal Sticking

[mjwalsh]

Because of an intermittent problem of the original switches sticking, soon we will be replacing the 2 float switches in our RO tank with the following:
https://www.kleen-ritecorp.com/p-17371-ro-storage-tank-float-switch.aspx

From other operators experience ... I was wondering if these are the best switches for a 50" height x 26" diameter plastic barrel RO storage tank? Maybe some of you have suggestions when it comes to the ideal positioning & weights needed for installing these float switches.

The old float switches have proven to have lasted for over 20 years but that specific brand from the now defunct Specialty Equip do not appear to be available anymore. Both on the overflow & the low water cutoff floats the mechanicals within the switches are no longer reliable enough for unattended switching.

 

[Main Street Carwash]

I have a float switch like that on my RO tank at one of my washes. It just hangs by the cord from the top of the tank about 12 inches from the top (or whatever level you like). When the product gets low enough for the switch to no longer float and becomes vertical from hanging by the wires, the pump runs to top off the tank. When the level of product rises sufficiently to float the switch causing it to become horizontal again, it shuts the pump off. In this particular setup I do not have a low water cutoff switch in the tank because the site is checked multiple times daily and the tank being low would be noticed long before it ran dry. But to add another for low cutoff would be the same principle just near the bottom of the tank.

 

[Jim L.]

I've been using these(5) since I opened. I think I've had to replace only one once.

https://www.amazon.com/Baomain-Cabl...1&sr=8-3&keywords=float+switch+for+water+tank

 

[mac]

The older ones did last forever because they used mercury as the conductor. Since that is now bad for us, like people used to eat the switches or something, they all went to mechanical parts internally, and those simply wear out. Sometimes intermittently.

 

[MEP001]

I've been using these(5) since I opened. I think I've had to replace only one once.

https://www.amazon.com/Baomain-Cabl...1&sr=8-3&keywords=float+switch+for+water+tank

Those are a Chinese made replica of the Specialty Equipment switches. I bought some off an eBay seller, and even though they claim to be rated for 15 amps the cord is WAY too thin to carry that much current at 120 volts. It looks to be 18 gauge or maybe even smaller. You'll notice they've concealed the wire ends in the Amazon photo.

The Kleen-Rite ones work great.

 

[Randy]

MDI still makes excellent mercury float switch. https://www.mdius.com/

 

[mjwalsh]

MDI still makes excellent mercury float switch. https://www.mdius.com/

It looks like the tetherless could have its advantages with its built-in weight. https://www.mdius.com/liquid-level-controls/mechanical-floats/internally-weighted-tetherless-floats

With 2 of the higher amps MDIs we could actually eliminate a control relay or 2 possibly just letting the refill & stop refilling controlled just by using the higher amp rated MDIs. https://www.mdius.com/liquid-level-controls/mechanical-floats/high-amp-float-switch

 

[Earl Weiss]

Pricier but no moving parts. You could use it to open a solenoid valve.
https://www.supplyhouse.com/LevelGu...MI8Yat69jw3QIVh8DACh0cuwDLEAQYASABEgIMrPD_BwE